CVE-2024-51998 in changedetection.io
Summary
by MITRE • 11/08/2024
changedetection.io is a free open source web page change detection tool. The validation for the file URI scheme falls short, and results in an attacker being able to read any file on the system. This issue only affects instances with a webdriver enabled, and `ALLOW_FILE_URI` false or not defined. The check used for URL protocol, `is_safe_url`, allows `file:` as a URL scheme. It later checks if local files are permitted, but one of the preconditions for the check is that the URL starts with `file://`. The issue comes with the fact that the file URI scheme is not required to have double slashes. This issue has been addressed in version 0.47.06 and all users are advised to upgrade. There are no known workarounds for this vulnerability.
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Analysis
by VulDB Data Team • 11/08/2024
The vulnerability identified as CVE-2024-51998 affects changedetection.io, a widely used open source web page change detection tool that enables users to monitor website content changes. This security flaw represents a critical path traversal vulnerability that allows remote attackers to access arbitrary files on the system through improper validation of file URI schemes. The vulnerability specifically targets installations where the webdriver functionality is enabled and the ALLOW_FILE_URI configuration parameter is set to false or not explicitly defined, creating an exploitable condition that undermines the application's security boundaries.
The technical implementation of this vulnerability stems from inadequate validation logic within the application's URL protocol checking mechanism. The existing `is_safe_url` function incorrectly permits the `file:` URI scheme without proper enforcement of the required double slash notation that defines the standard file URI format. This validation flaw occurs because the system fails to properly distinguish between legitimate file URI schemes that require the `file://` prefix and malformed variants that might bypass security checks. The vulnerability specifically exploits the fact that while the application checks for `file://` prefix, it does not enforce the strict URI scheme syntax that requires double slashes, allowing attackers to construct malicious file paths that circumvent intended security restrictions.
The operational impact of this vulnerability is severe and potentially catastrophic for affected systems, as it enables unauthorized file system access that could lead to data exfiltration, system compromise, and privilege escalation. Attackers can leverage this vulnerability to read sensitive files including configuration files, database credentials, application source code, and potentially system-level information that could facilitate further attacks. The attack vector is particularly dangerous because it requires minimal privileges to exploit and can be executed remotely, making it an attractive target for threat actors seeking to gain unauthorized access to systems running vulnerable versions of changedetection.io. This vulnerability directly relates to CWE-22, which describes improper limitation of a pathname to a restricted directory, and aligns with ATT&CK technique T1083 for discovering system information and T1566 for credential access through exploitation of web applications.
The vulnerability has been addressed in version 0.47.06 of changedetection.io, which implements proper URI scheme validation and enforces strict compliance with the standard file URI format. Security researchers and system administrators should prioritize upgrading to this patched version to eliminate the risk of exploitation. The vulnerability affects installations where webdriver functionality is enabled and the ALLOW_FILE_URI parameter is not explicitly set to true, making it particularly relevant for organizations using the application in production environments. No effective workarounds exist for this vulnerability, as the issue stems from fundamental validation logic that cannot be easily bypassed without modifying core application functionality, emphasizing the importance of immediate patch deployment for all affected systems. Organizations should conduct comprehensive security assessments to identify all instances of the vulnerable software and ensure proper configuration of the ALLOW_FILE_URI parameter to prevent unauthorized file access attempts.